Molecular Design Of Octaprismane And Dipicrylamine Derivatives For High Energy Density Compounds

Nowadays,the main purpose of developing new energetic materials is to reach a fine balance between high explosive performance and low sensitivity for novel high energy density materials?HEDMs?.Many studies are focusing on cage compounds and aromatic compounds due to their advantages of large crystal density and large strain force.Thus,in the present work,we have designed a series of cage compounds and aromatic compounds and predicted the detonation performance and stability of the target compounds using density functional theory?DFT?.Main parts of the study are as follows:1.Poly-nitro octaprismane derivativesWe designed four poly-nitro octaprismane compounds by incorporating nitro groups into octaprismane,namely,octanitrooctaprismane?ONOP?,octanitrooctaazaprismane?ONOAP?,tetranitrooctaprismane?TNOP?,and tetranitrooctaazaprismane?TNOAP?.The DFT methods have been employed to optimize molecular structures and to predict the detonation properties and stability of the designed molecules.The results show that ONOP,ONOAP and TNOAP exhibit better detonation performance than HMX.The bond dissociation energies of the molecules indicate that all the compounds display excellent thermal stability,except for ONOP,which also meets the thermal stability requirement as HEDMs.TNOAP is found to be a highly powerful compound with appropriate sensitivity,thus we recommend this molecule as the best candidate for advanced HEDMs.2.DipicrylaminederivativesDFT calculations were performed to look for potential energetic materials and discuss the effects of various substituents?-NO₂?-CN?-NH₂?-N₃?-NHNO₂,and-ONO₂?.The results show that the detonation performance of all designed molecules are superior to TNT and ten of the target molecules display better detonation property than RDX.All investigated dipicrylamine?DPA?derivatives are expected to be thermally stable because bond dissociation energies of trigger bond are more than 170 kJ/mol.Moreover,most of the designed molecules have larger h₅₀ than CL-20.Taking both detonation properties and stability into consideration,D4,D5,and E5 are recommended as potential energetic materials.3.Polynitro-substituted uric acid derivativesFifteen poly-nitro uric acid derivatives were designed through substituting the hydrogen atoms in uric acid with nitro group.The detonation properties of all molecules were evaluated according to Kamlet-Jacobs equations and specific impulses.Calculated results show that there are good linear relationships between detonation heat,densities,detonation velocities,detonation pressures and the numbers of nitro group,respectively.It is found that tri-nitro and tetra-nitro uric acid derivatives show detonation velocity of about 8.0 km/s,and detonation pressure of 30 GPa,and most of the investigated molecules have higher specific impulse than that of RDX.By analyzing bond dissociation energies?BDEs?of N-NO₂ bonds,impact sensitivity,and the free space per molecule in the unit cell,the most of investigated molecules exhibit satisfactory stability.